Device for controlling the action of a fluid under pressure



April 14, 1936. SHERTZ ETAL 2,037,627 A,

DEVICE FOR CONTROLLING THE ACTION OF A FLUID UNDER PRESSURE I Filedseptj4, y1934 s sheets-sheet 1 A pl'il 14,1936. .5 HERTZ ET AL 2,037,627

DEVICE FOR CONTROLLING THE ACTION OF' A FLUID UNDER PRESSURE Filed sept.4, 1954 v5 sheets-sheet' z pril'14, 1936. s HER-fz ET A1.

DEVICE FOR CONTROLLING THE ACTION OF A FLUID UNDER PRESSURE- 3Sheets-Sheet 3 Filed Sept. 4, 1934 l N V E N T O R 5 Jaw/5245 MHZ,

AT T0 RNE-YS Patented Apr. `14, 1936 UNITED STATES PATENT OFFICE DEVICEFOR CONTROLLING THE ACTION OF A FLUID UNDER PRESSURE France ApplicationSeptember 4, 1934, Serial No. 742,672 In Belgium September 13, 1933 10Claims.

The present invention relates to devices for controlling the action of afluid under pressure and it is more particularly' concerned with devicesfor controlling the action of a gaseous fluid,

such for instance as compressed air.

The object of the present invention is to provide a device of the typeabove referred to which is better adapted to comply with therequirements of practice and especially which moderates and renders lesssudden the action of theY fluid under pressure on the apparatus to beoperated by said fluid, so as to reduce the wear and tear of saidapparatus.

The essential feature of the present invention 1; consists in providinga relay which first causes the uid to be fed to said apparatus with agradually increasing pressure, a valve for feeding the fluid at fullpressure to said apparatus, and a mechanism operated by the fluid underpressure in said relay for opening said valve When said pressure in therelay reaches a predetermined value.

According to a first embodiment of the present invention, this controlmechanism consists of two pistons rigid with each other and only one ofwhich is rst subjected to the action of thefluid under pressure from thereservoir of fluid., the surface of this piston being too small forallowing the valve to be forced open; means operative by the fluid underpressure in the relay subsequently causing the fluid from said reservoirto act on the second piston, the active surface of which is such thatthe combined actions of the fluid under pressure on both pistonsovercome the resistance of the valve and open it.

According to another embodiment of the invention, the control mechanismconsists of two pistons movable with respect to each other but adaptedto bear against each other, only one of these pistons being subjected tothe action of the fluid under pressure from the reservoir, this pistonbeing of such aV surface that this action is not suicient for overcomingthe resistance of the valve, the space between the two pistons being ,5connected with the inside of the relay so that the fluid under graduallyincreasing pressure fed to said space finally causes the second piston,the surface of which is much larger than that of the first one to forcesaid valve open.

According to a third embodiment of the present invention, the controlmechanism of the valve consists of a single piston, and throttling meansare provided for causing the fluid from said reservoir to act on saidpiston with a progressively 55 increasing pressure, whereby, after acertain time the action exerted on said piston is sufcient forovercoming the resistance of the valve and forcing it open; otherthrottling means are provided for the ow of the fluid through said relayto the apparatus to be actuated by said fluid, before 5 the opening ofthe valve.

These and other features of the present invention will appear from thefollowing detailed description of specific embodiments of saidinvention.

Preferred embodiments of the present invention will be hereinafterdescribed, with reference to the accompanying drawings, given merely byway of example and in which:

Fig. 1 is a diagrammatic general View of a 15 system embodying the fluidcontrolling device according to the present invention;

Fig. 2 is a sectional view of an embodiment of the device according tothe present invention;

Fig. 3y is a sectional View of another embodiment 20 of the invention;

Fig. 4 is a diagrammatic general View of a system as illustrated by Fig.1, showing in section a third embodiment of the control device accordingto the present invention;

Fig. 5 is a diagram showing the pressure curves.

According to Fig. 1, an apparatus A is to be actuated by means of acompressed fluid (compressed air for instance)v present in a reservoirI. This apparatus A may be of any type whatever (braking apparatus,starting device for internal combustion engines, etc.), but it will bereadily understood that the parts of this apparatus, for instance apiston and a cylinder movableV with respect to each other, should not besuddenly subjected to the full pressure of the fluid inA reservoir I, asa sudden action of the fluid would rapidly deteriorate and even breakthese parts.

In order to obviate this drawback, there is provided, according to thepresent invention, a relay R including:

(a) means for feeding, in a first step of the operation, fluid at agradually increasing pressure, lower than the pressure in reservoir I,to apparatus A, this fluid being fed from reservoir I? through pipes I5and I4, controlled for instance through a valve C operated in anysuitable manner, and 50 (b) a valve for admitting, in the second step ofthe operation, fluid at full pressure, through conduit I2, into conduitIIJ and apparatus A, this valve being actuated by the control mechanismof the relay, which is adapted to automatically open the valve at theend of the rst step of the operation.

In order to obtain this result, the relay includes a passage ofrestricted section of ilow for throttling the stream of fluid fed to therelay during the first step of the operation. This throttling passage Emay be either independent of Valve S and control plunger B, or combinedtherewith, as shown in Figs. 2, 3 and 4. According to the presentinvention, the control plunger B is rst subjected by the liquid or gasunder pressure to an action which brings it into contact with the valve,without opening said valve, and then to another action by the fluid4under pressure which causes said valve to open when the pressure in therelay reaches a predetermined value h which is independent of the actualpressure of the fluid in reservoir l.

According to a rst embodiment of the invention, shown in Fig. 2, plungerB advantageously comprises two active surfaces T1 and T2 intended to besubjected to the action of the fluid under pressure from the reservoir,the rst one as soon as the relay is brought into action, and the secondone at the end of the rst step of the operation,

the active area of these surfaces being such that the forces theytransmit to valve S are respectively lower and higher (and of oppositedirections) than the force that tends to keep the Valve applied againstits seat under the effect of the pressure I-I of the reservoir.

The device further includes a distributing system F, adapted to beactuated by the pressure h in conduit l and to bring into operativecontact vwith surface T2 the air under pressure H of the reservoir.

'Ihis piston will for instance consist of two piston elements 22 and 2|located one above the other.

Piston element 2|, which is of a diameter D1 smaller than the diameter Dof the seat of valve S is mounted in a cylinder 23 provided with achamber 24 surrounding piston element 2|. Said piston element issubjected to the action of the fluid under pressure fed through pipe |4into this chamber 24.

The other piston element 2|, which is of a diameter D2 larger than thediameter D of the valve seat, is slidable in a cylinder 25 provided inthe casing Il of the relay. This piston 2| is rigid with a prolonged,preferably stepped, part 26, 21, 28 the end 28 of which is adapted tocome into contact with valve S.

The whole of the two piston elements is subjected to the action of aspring 29.

Valve S is mounted, in coaxial relation with these piston elements inthe case into which opens a pipe l2 directly connected with reservoir l.This Valve is subjected to the action of a relatively weak spring leurging it toward its seat.

If the passage of throttled section E is provided in the vicinity of theextremity 28 of the piston, said passage communicating with chamber 24through Conduit SQ provided in the piston, the whole can be arranged insuch manner that, when piston Ztl- 2| is in the position of rest, achamber iii provided on the inside of the casing of the relay is incommunication With chamber 25 through passage 3|, said chamber 25 beingitself connected with the atmosphere through a port 32, while when thispiston 2li- 2| is in its operative position, portion 2l of this pistonunit closes this passage 3|, which consists for instance of a leatherelement. chamber I6 now being in communication with chamber 24 andconduit 4 through throttled passage E.

As for the distributing system above referred to and designated byreference letter F, it may be of any suitable type and consists, forinstance of a slide valve arrangement controlled by a piston 22 movablein a cylinder 33 and subjected on the one hand to the action of a spring221 of suitable strength, eventually adjustable, and, on the other hand,to the action, directly opposite, of the liquid under pressure h presentin the chamber I6 of the relay.

The slide valve arrangement comprises, for instance, a rod 34 rigid Withpiston 22 (or suitably connected thereto) slidable inside a plug 35screwed in bore 33 and p-rovided with a part 35 of reduced crosssectional area adapted to establish a connection between two ports 3land 38. When piston 22 is pushed up by the iluid under pressure inchamber i6 against the action of its spring 221, (the upper part ofcylinder 33 being connected with the atmosphere through port 33) the rod36 connects two chambers 39 and 49 through these ports 3'! and 38.

Therefore, if these ports are themselves connected to chamber 24 and theend of cylinder 25 respectively, the compressed fluid fed into thischamber 24 is allowed to flow against the surface T2 of piston 2|.

These ports S1 and 38 open for instance, in the lateral surface of plug35, into annular grooves 4| and 42 respectively. Groove 4| is connected,through another annular groove 45 and port 43, With a duct 46 openinginto chamber 24. Groove 42 is connected with the end of cylinder 25 inwhich is located surface T2.

The operation of the device abo-ve described is the following:

In order to operate apparatus A, it suflices to act on valve C so as toconnect chamber 24 with reservoir I through conduit I4. Pistons 20-2Iare then moved downwardly, compressing spring 29 and the end 28 ofpiston 2| comes into contact with valve S. But as the fluid underpressure acts only on surface T1, the force transmitted by the pistonsis not suicient for opening valve S.

At the same time the communication between chamber I6 and chamber 25 iscut off, andthe pressure due to the inflow of air through throttledpassage E begins to rise in chamber i5 and conduit I9, owing to theresistance opposed to the displacement of the parts of apparatus A. Whenthis pressure reaches a predetermined value, it pushes piston 22 againstthe action of its spring 221, so that surface'T2 is now connected withchamber 24 through conduit 43, distributing device F and conduit 44.

It follows that, since the pressure of the fluid from reservoir now actson both of the surfaces T1 and T2, the resulting force transmitted bypiston 2li-2| is sufficient for opening valve S. The full pressure ofthe fluid in reservoir l is now transmitted to chamber i6 and conduitI6.

When it is no longer desired to operate apparatus A, it suiiices tooperate valve C in the opposite direction so as to bring conduit I4 intoconnection with the atmosphere.

In relay R, pistons 2-2| are then brought back into their initialposition; valve S is brought back onto its seat and the compressed airpresent in apparatus A escapes to the atmosphere through conduit l0,chamber I@ and port 22. The auxiliary piston 22 then comes back to itsinitial position and the whole mechanism is again ready for a newoperation.

The device which has just been described, while exerting a relativelysudden and strong action on apparatus A, avoids any destruction of thisapparatus because the application of this action is preceded by aprogressive increase of the pressure up to a predetermined value.

If, for instance, apparatus A includes a clutch device provided withjaws adapted to come into mesh during the first step of the operation,the engagement of these jaws with one another can take place verysmoothly.

It is very important to note that the value of pressure h for which thedistributing device F is brought into play remains the same irrespectiveof the value of the uid pressure in reservoir I and even when this fluidpressure has dropped due, for instance, to repeated operations lof thedevice.

Finally, the pressure in conduit I and in chamber IB rises only if theparts of apparatus A offer a suitable resistance.

supposing, for instance, apparatus A to be a starter for internalcombustion engines of the Diesel type, if the engineer inadvertentlyoperates the starter when the engine is already started, the pressure inchamber I6 cannot rise because there is no mechanical resistance to theworking of starter A, and therefore the second step of the operationdoes not take place. This feature prevents a possible breakage of theapparatus and a waste of compressed air.

In the embodiment of Fig. 3, pistons |02 and |03 are disposed in linewith each other and are preferably separated from each other by aleather disc |I5, or the equivalent. The piston of larger diameter |03is located next to chamber I6. Advantageously, the diameter of the otherpiston |02 is substantially equal to the diameter of the active surfaceof valve S.

The compressed air fed by conduit I4 into cylinder I I2 which cooperateswith the piston I 02 of smaller diameter, can penetrate into chamber I6through a conduit |I0 extending through said piston and fixed therein ina fluidtight manner, for instance by soldering. Conduit IIO also extendsthroughout piston |03 but without being fixed thereto.

Ihe end of this piston |03 forms, opposite valve S, a hollow rod |04 ofa diameter substantially equal to that of the aperture |09 of a packingmember |091, for instance of leather, interposed between cylinder I I3,which cooperates with piston |03, and chamber I6.

This rod |04 is prolonged by a part of smaller diameter |05, also hollowfor affording a passage for conduit IIO.

Furthermore conduits III are provided in rod |04 in such manner that,after this rod has penetrated into passage |09, chamber I6 cancommunicate with the inner chamber II2 provided in rod |04. This chamberII2 itself communicates through ports II3 and ||4 with the activesurface of piston |03, that is to say with the space between pistons |02and |03.

Piston |03 is subjected to the action of a return spring |01, and valveS is subjected to the action of a return spring I9. Finally escape portsII Ii and III are provided in cylinders II2 and |I3.

This device works in the following manner:

As in the preceding embodiment, the relay is brought into action byoperating valve C interposed between pipe elements I4 and I5 whichconnect cylinder II2 with reservoir I. The compressed air, coming intocontact with the smaller piston |02, causes it to move downwardly,pushing piston |03 also downwardly.

The end of the rod |04 then comes into contact with Valve S, but theforce applied to the whole of the two pistons is not suiiicient forcausing valve S to open.

The upper face of this Valve is provided with a small concave slot |06so that, after the end I 05 of piston |03 has come into contact with thevalve, the air coming through conduit IIO can escape into chamber I6 byflowing through this slot.

In the course of this downward movement, the rod |04 of piston |03closes passage |09. The air coming into chamber I6 causes the pressuretherein to rise. Furthermore, this air under pressure flows, throughpassages III, II2, II3 and II4, into the space between pistons |02 and I03.

The active face of piston |03 is then subjected to the action of anincreasing pressure until, for a certain value p of this pressure, thetotal effort applied on both pistons is suflicient for opening valve S,against the action of springs |01 and I9. Air at full pressure fromconduit I2 is then admitted into chamber I6.

It is possible to ascertain the forces that yare acting at this time. Inthe following table, I have shown on the left hand sidev the forcesacting to open the Valve S, and on the right hand side the resistancesacting in the opposite direc- -Y tion:

Forces Resistances Force d resulting from the action of the pressure Pof the reservoir on valve S.

Force e resulting from the action of pressure p on the under face oi rod104.

Force f resulting from the action of pressure p on the under face ofpiston 102.

4. Resistance g of spring 107.

5. Resistance h of spring 19.

6. Internal resistances l.

l. Force a resulting from the acl. tion of the pressure P of thereservoir on piston 102.

2. Force b resulting from the action 2. of pressure p en the activesurface of piston 103.

3. Force c resulting from the action 3. of pressure p on the upper face0i valve All these values are constants or depend only on pressure p. Itis therefore possible to calculate the diameter of piston |03 and thestrengths of springs |01 and I9 in such manner as to obtain the openingof valve S for a predetermined value of pressure p.

The equality of the areas of piston |02 and valve S makes it possible towholly eliminate the action of the pressure P of reservoir I, which isimportant because this pressure P is more or less variable.

The working of the relay for opening the valve has been above explained.It can easily be seen that the closing of the valve S is obtained bybringing Valve C into the position that connects conduit I4 with theatmosphere. In this case, piston I 02 is itself connected with theatmosphere through conduit I4 and Valve C. This piston therefore comesback into its initial position under the action of the pressure P thatexists at this time in chamber I6. Central conduit I I0 and disc I5 arecaused to move together with piston |02. But piston |03 remains in itslower position, owing to the high pressure P acting on its upper face.

When coming back to its initial position, piston il?? uncovers orifices||6, so that the air presentbetween the two pistons escapes throughthese orifices. The larger piston |03 then moves upwardly, together withrod |04 which reopens passage it through which the air of chamber I6 canpass to the escape orifices Valve S is then brought back into contactwith its seat and the whole device is back in its initial state, readyfor another operation.

It is generally of advantage to reduce the diameter of the larger piston|03, in order to reduce the space occupied. by the relay. For thispurpose, it is possible to provide around the part of piston to2 that isin contact with disc ||5 (which part is of reduced diameter) a packingmember analogous to leather element |091. Under these conditions, thecounter-pressure p would act only on this part of reduced diameter andthe area of the larger piston might be reduced by an amount equal to thedifference between the whole area of piston |02 and the part of reduceddiameter of this piston.

According to another embodiment of the invention, shown by Fig. 4, relayR includes only one piston |28 having a hollow rod |2|. The lower end ofrod |2| closes passage |22 as soon as piston l2@ is urged in a downwarddirection, that is to say toward the valve. Reservoir communicates withspace B1 above the piston through a conduit I4, I5 provided with a threeway cock C. Furthermore, a throttling device 23 is provided before thiscock and a second throttling device |24 is provided at the entrance intospace B1. Preferably, rod |2| is also provided, at its lower part, witha third throttling device 25.

The working of this device is illustrated by the curves of Fig. 5. Whencock C is opened, a gradually increasing pressure is exerted on pistonlio, bringing rod itl into Contact with valve S. Air then flows intochamber I6 through orifices l2., and 325 and the pressure slowly rises.As soon as it reaches a predetermined value p, the force applied topiston becomes suflicient for opening valve S.

In order to stop the operation it suffices to turn cock C in such manneras to connect chamber B1 with the atmosphere.

Fig. 5 shows the variation of pressure P respectively in reservoir inchamber Bl and in chamber l5, as a function of time T. The p-ressure inreservoir is represented by a line X which is nearly horizontal, whilethe curves Y and Z rep-resent the pressures in chambers Bl and it. Thenearly vertical portion of curve Z corresponds to the opening of valveS.

lit will be easy for someone skilled in the art to calculate thesections of passages |23, |24, |25 with a view to obtaining curves ofthe desired shape.

While I have, in the preceding description, disclosed. what I deem to bepractical and efiicient embodiments of the present invention, it shouldbe well understood that I do not wish to be limited thereto as theremight be changes made in the arrangement, disposition and form of theparts without departing from the principle of the present invention ascomprehended within the scope of the appended claims.

What is claimed:

l. In a system including a reservoir of fluid under pressure, anapparatus to be actuated by said uid under pressure, and a conduit forconnecting said apparatus with said reservoir, a device for controllingthe feed of fluid under pressure from said reservoir to said apparatus,which comprises, in combination, a valve in said conduit for controllingthe flow of fluid therethrough, said valve being normally closed, apassage normally connecting the portion of said conduit between saidapparatus and said Valve with the atmosphere, means operative by thefluid under pressure from said reservoir for stopping said passage,means including a passage of restricted cross section for feeding fluidunder pressure from said reservoir to said portion of the conduit,whereby the pressure in said portion of the conduit gradually rises upto a predetermined value, and means operative by the iiuid underpressure for opening said valve.

2. In a system including a reservoir of iiuid under pressure, anapparatus for use by said iiuid under pressure, and a conduit forconnecting said apparatus with said reservoir, a device for controllingthe feed of iiuid under pressure from said reservoir to said apparatus,which comprises, in combination, a valve in said conduit for controllingthe iiow of fluid therethrough, said valve being normally closed, apassage normally connecting the port-ion of said conduit between saidapparatus and said valve with the atmosphere, a movable member operativeby the fluid under pressure from said reservoir, means operative by saidmember for stopping said passage when said member is subjected to thepressure from said reservoir, said l member being provided with a ductof restricted cross section for feeding uid under pressure from saidreservoir to said portion of the conduit, whereby the pressure in saidportion of the conduit gradually increases up to a predetermined value,and means operative by the uid present in said portion of the conduit atthis predetermined value of the pressure for opening said valve.

3. In a system including a reservoir of iiuld under pressure, anapparatus to be actuated by said fluid under pressure and a conduit forconnecting said apparatus with said reservoir, a device for controllingthe feed of fluid under pressure from said reservoir to said apparatus,which comprises, in combination, a hollow casing directly connected atone end with the portion of said conduit that leads to this apparatus, avalve interposed between the other end of said casing and the portion ofsaid conduit that leads to this reservoir adapted to control the flow oifluid to said casing, elastic means for urging said valve toward itsclosed position, a passage in said casing for normally connecting theinside thereoi with the atmosphere, two cylinders of diferent diametersin line with each other, two piston elements rigid with each otherslidably fitting in said cylinders respectively and adapted to act onsaid valve for opening it, means for feeding uid under pressure fromsaid reservoir to the cylinder of smaller diameter so as to cause it toact on the smaller piston, means carried by said pistons for stoppingsaid passage when said smaller piston is subjected to the pressure fromsaid reservoir, said pistons being provided with a duct of restrictedsection connecting the cylinder of smaller diameter with the inside ofthe casing, whereby the pressure in said casing gradually rises up to apredetermined value when fluid under pressure is fed to said cylinder ofsmaller diameter, a normally closed passage for connecting these twocylinders with each other, and means operative by the fluid present insaid casing when the pressure thereof has reached this predeterminedvalue for opening this last mentioned passage.

4. A device according to claim 3 further comprising a spring opposingthe movements of said pistons in the direction that tends to open saidvalve.

5. In a system including a reservoir of fluid under pressure, anapparatus to be actuated by said fluid under pressure, and a conduit forconnecting said apparatus with said reservoir, a device for controllingthe feed of fluid under pressure from said reservoir to said apparatus,which comprises, in combination, a hollow casing directly connected atone end with the portion of said conduit that leads to this apparatus, avalve interposed between the other end of said casing and the portion ofsaid conduit that leads to this reservoir adapted to control the ow offluid to said casing, elastic means for urging said valve towards itsclosed position, a passage in said casing for normally connecting theinside thereof with the atmosphere, two cylinders of different diametersin line with each other, two pistons adapted to bear against each otherslidably tting in said cylinders respectively, means carried by thelarger piston adapted to act on the smaller piston for opening it, meansfor feeding fluid under pressure from said reservoir to the cylinder ofsmaller diameter so as to cause it to act on the smaller piston, whichin turn pushes the larger piston, means carried by the larger piston forstopping said passage when said smaller piston is subjected to thepressure from said reservoir, said smaller piston being provided with aduct of restricted section of ow extending throughout the larger pistonfor connecting the cylinder of smaller diameter with the inside of thecasing,

l whereby the pressure in said casing gradually rises up to apredetermined value when fluid under pressure is fed to said cylinder ofsmaller diameter, and a passage in said larger piston for connecting theinside of the casing with the larger cylinder whereby the pressure ofthe fluid present in said casing causes said larger piston to open saidvalve.

6. A device according to claim 5 further comprising elastic meansopposing the displacement of said larger piston in the direction thatcorresponds to the opening of said valve.

'7. In a system including a reservoir of fluid under pressure, anapparatus to be operated by said fluid under pressure, and a conduit forconnecting said apparatus with said reservoir, a device for controllingthe feed of fluid under pressure from said reservoir to said apparatus,which comprises, in combination, a hollow casing directly connected atone end with the portion of this conduit that leads to this apparatus, aValve interposed between the other end of said casing and the portion ofsaid conduit that leads to this reservoir adapted to control the flow ofiiuid to said casing, elastic means for urging said valve toward itsclosed position, a passage in said casing for normally connecting theinside thereof with the atmosphere, a cylinder connected with saidcasing, a piston slidably fitting in said cylinder adapted to act onsaid valve for opening it, means including at least one passage ofrestricted section of flow for feeding fluid under pressure from saidreservoir into said cylinder, means carried by said piston for stoppingsaid passage when said piston is subjected to the pressure of this uid,said piston being provided with a duct of restricted section of flow forconnecting said cylinder with the inside of the casing, whereby thepressure in said casing gradually rises when fluid under` pressure isfed to said cylinder, and a spring opposing the movements of said pistonin the direction that corresponds to the opening of said valve.

8. A device according to claim 5 in which the diameter of said smallerpiston and the diameter of the active surface of said valve aresubstantially equal.

9. In a system including a reservoir of fluid under pressure, anapparatus to be operated by said fluid under pressure, and a conduit forconnecting said apparatus with said reservoir, a device for controllingthe feed of fluid under pressure from said reservoir to said apparatus,which comprises, in combination, a hollow casing directly connected atone end with the portion of said conduit that leads to the apparatus, avalve interposed between the other end of said casing and the portion ofsaid conduit that leads to the reservoir adapted to control the flow offluid to said casing,a passage in said casing for normally connectingthe inside thereof with the atmosphere, a cylinder connected with saidcasing, a piston slidably tting in said cylinder adapted to act on saidvalve for opening it, means including another valve adapted to beactuated by hand for feeding fluid under pressure from said reservoirinto said cylinder, means carried by said piston for stopping saidpassage when said piston is subjected to the pressure of this fluid,said piston being provided with a duct of restricted section of iiow forconnecting said cylinder with the inside of the casing, whereby thepressure in said casing gradually rises when uid under pressure is fedto said cylinder, and a spring opposing the movements of said piston inthe valve-opening direction of said piston.

10. In a system including a reservoir of fluid under pressure, anapparatus to be operated by said fluid under pressure, and a conduit forconnecting said apparatus with said reservoir, a device for controllingthe feed of fluid under pressure from said reservoir to said apparatus,which comprises, in combination, a hollow casing directly connected atone end with the portion of the conduit that leads to the apparatus, avalve interposed between the other end of said casing and the portion ofsaid conduit that leads to the reservoir adapted to control the flow offluid to said casing, a cylinder connected with said cas- DENISE HERTZ,NE DAVID. Eecutor of Stanislas Hertz, Deceased. MAURICE PIERRE BERGER.

